COLORED FATS 399 



was found that the acid hydrolyzed from the ester was not exclusively 

 palmitic acid, as had been the case with phj^salien, but was a mixture of 

 saturated and unsaturated acids. A fractionation of the acid showed that 

 45% was unsaturated, and that this contained exclusively oleic acid. From 

 the saturated acids (55%) pure preparations of carnaubic, myristic, and 

 palmitic acids were prepared, the last two in the preponderate amount. 

 Only minor amounts of stearic acid were combined with capsanthin, al- 

 though it could be isolated on saponification of the mother liquor from 

 the colorless esters. 



Zechmeister and Cholnoky^^^ prepared a number of synthetic fatty acid 

 esters of capsanthin by the method employed by Kuhn et al^^^ for zeaxan- 

 thin and by Karrer and Ishikawa for lutein (xanthophyll).*^*'*^^ When 

 the purified cajisiuithin was treated with the ucyl chlorides of a number of 

 acids in pyridine, estcrification ensued. When methyl alcohol was added, 

 the ester precipitated. It was found that two acyl groups were present per 

 molecule of capsanthin, since it contained two hydroxyl groups. The 

 following products were synthesized: 



M.p .,° 



C:ip8;uithiu diacetate 145-146 



Capsanthin dipropionatc 140 



Capsanthin dicaprate 102 



Capsanthin dimyristate 88 



Capsanthin dipalmitate 85 



Capsanthin distearate 84 



Capsanthin dioleate Liquid 



Capsanthin dil)enzoatc 121-122 



The melting point falls as the fatty acid chain is lengthened, probably 

 because it approaches that of the fatty acid as this element becomes more 

 predominant than the capsanthin. The solubility in methanol is also de- 

 creased when the fatty acid chains of the esters are lengthened. The 

 esters are readily obtained in crystalline form. 



It would thus seem that carotenols, as well as the sterols, higher alcohols, 

 or glycerol, may serve for the estcrification of fatty acids. The fatty acids 

 react with the molecule available at the spot where synthesis occurs. 

 There does not seem to be much selectivity exerted, although it is believed 

 by some that cholesterol favors a combination with the unsaturated acids. 

 The colorless vitamin A esters are in the same category as the colored 

 esters. These will be considered in the chapter on vitamin A. 



An interesting unexplored field is concerned with the nature and dis- 

 tribution of mixed esters of the carotenols. Although the dipalmitate 



■•" 11. Kuhn, A. Wintenstoin, and W. Kaufmann, Ber., B63, 1489-1497 (1930). 

 «3 l>. Ivarrcr and S. Ishikawa, lielv. Chim. Ada, IS, 709-713 (1930). 

 *2' P. Karrer and S. Isiiikawa, Hclv. Chim. Ada, 13, 1099-1102 (1930). 



